Can a wool blanket be machine washed?

Yes. but if you wash it with cold water it will shrink. Cold water and 1 1/2 cups of salt. It stops the color(s) from running. After washing in cold water spread out on a sweater rack, and if you don't have one, spread it out on a thick towel then roll the towel to get the excess dampness out of the sweater; put on another dry thick towel and spread sweater across it to air dry (gently pull sweater into shape and run palms down the sweater to get any wrinkles out.)